Ciudad Cancún is a different story. Avenida Tulum is lined with local restaurants, and most have outdoor tables. Look for places where locals congregate if you want authentically prepared Yucatecan dishes like sopa de lima—soup with a chicken broth base, vegetables and a tangy dose of fresh lime juice—or poc-chuc, spicy marinated pork grilled with onions.
One local favorite—and a place where you can sample home-style cooking for a fraction of the cost of the Hotel Zone restaurants—is Checándole, downtown at Av. Xpuhil #27 (near Mercado 28). It serves tacos, steak tampiqueña, enchiladas with mole sauce and other Mexican standards, along with fresh fruit juices. From the Hotel Zone, a Ruta 6 bus will get you there.
For a reasonably priced Mexican-style breakfast try one of Cancún's coffee shops. At Vips, a popular chain with branches all over the country, you can order standards like huevos motuleños—two fried eggs, peas and diced ham atop a crispy tortilla covered in tomato sauce, with pureed black beans and slices of fried banana on the side. This, plus toast, orange juice and good cafe americano, will fill you up for about $10. The Hotel Zone Vips is next to the Cancún Center.
Restaurants in the large hotels use purified water for cooking and for washing produce; inquire about this health procedure specifically at places to eat on the mainland. In general, avoid ice cubes in drinks unless you know purified water has been used, and stay away from uncooked fruits and vegetables. See the Lodgings & Restaurants section for AAA Diamond designated nearby restaurants.